There are many different types of envelopes in use today, and a great number of these envelopes are for special uses or purposes. One of these special uses is in the computer field wherein an envelope is required to store magnetic recordings known as floppy disks. These envelopes must protect the magnetic disk and prevent it from being scratched or otherwise damaged. Inasmuch as many of these magnetic disks are stored, a portion of the envelope extends above the body of the envelope which stores the disk in order that identification means can be attached thereto for the purpose of retrieving the disks when needed. The prior art material out of which these envelopes is formed is a polyethelene material under the trademark name of "TYVEK."
These envelopes as formed in the prior art are unacceptable because the portion extending above the body of the envelope storing the disk is a panel that is so flimsy that with repeated handling, it becomes dog eared and droops so that it is difficult to locate a particular disk that is stored in the files. In order to overcome this disadvantage, the extended panels are made with double thickness in order to provide greater rigidity and durability. Further, instead of a single panel extending above the envelope body where the disk is stored, it is desired to have such envelopes with tabs protruding from the extended panel of the envelope for identification purposes with the tabs punched out such that they are located in approximately five different horizontal locations to provide easier access and visibility when searching for a particular disk, this poses a special problem in the prior art because with prior art machines, the envelopes have to be side guided for the punching to take place and the material TYVEK cannot be side guided. Thus, an additional machine or separate machine operation is required in order to form the necessary tabs in the top of the magnetic disk envelope. In either case, the cost is more expensive because of the additional machine or the time required to run the envelopes through an additional tab forming step for the separate machine operation.
Further, the blanks from which these envelopes are formed are required to go through a gluing operation which applies the glue to the proper locations prior to folding and forming the envelope itself. In one apparatus for applying glue to desired locations on the envelope blank, the blank passes between two rollers, one of which is a driving roller and the other of which is the glue application roller. If for any reason an envelope is not present as the glue application roller completes its circular movement, it applies the glue to the drive roller which of course creates problems inasmuch as the following envelope will receive glue not only on the top from the glue application roller but also on the bottom thereof from the drive roller. The unit must then be stopped and the drive roller cleaned before the machine can continue to be operated. The prior art method of avoiding this problem has been to use a finger switch which closes when no envelope is present to be glued, thus completing part of a circuit to a device for moving the drive roller out of contact with said glue application roller. Further, inasmuch as the drive roller needs to be moved out of contact with the glue application roller only when the glue application roller is in such a position as to apply glue to the driving roller, the position of the glue application roller must also be determined. In the prior art, a commutator element is attached to the glue application roller and makes electrical contact with a contact finger only when the roller is in the proper position to apply glue to an envelope passing between the glue application roller and the drive roller. Both the finger switch for detecting the presence of the envelope and the commutator switch for determining the proper position of the glue application roller are disadvantageous in that they wear with time and require adjustment with age in order to function properly. Again, of course, the adjustment or parts replacement cost is expensive and adds to the consumer cost of the envelopes.